For now, just listen to the music and try out the Fight, Act, Item and Mercy stuff.
I was planning to make the Toriel battle at first as that would be easiest, but her attack patterns aren't as simple as Papyrus, so I decided I would take another try at jumping mechanics for the Papyrus battle. Thanks to Toby Fox for the original game. Thanks to @FreddyRemixes and @russian-termatior for the music. Thanks to @goldmelonmaster for the sound effects.